Color filter substrate and preparation method thereof and display panel

Abstract

The present application discloses a color filter substrate, a preparation method thereof, and a display panel. The color filter substrate is characterized in that it comprises: a base substrate; a plurality of retaining walls arranged in an array on the base substrate; a pixel unit area disposed on the base substrate and located between adjacent retaining walls; wherein the surface of the retaining wall has a metal film layer, and the metal film layer includes silver. The color filter substrate of the present application can improve light extraction efficiency.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a color filter substrate and a preparation method thereof, and a display panel. Background Art

[0002] As a representative technology of new display, quantum dot display has received widespread attention in the industry. According to different light-emitting mechanisms, quantum dot display can be divided into two types: photoluminescent display and electroluminescent display. At present, photoluminescent quantum dot display is relatively mature. Due to the advantages of quantum dot materials such as high fluorescence quantum efficiency (PLQY), narrow half-peak width and easily adjustable emission wavelength, the display screen has a high color gamut and excellent picture quality. Quantum dot color film technology is a new generation of quantum dot display technology. It mainly combines red and green quantum dot color films with blue OLED, miniLED or microLED backlight, and uses short-wave blue light to excite red or green quantum dots to produce corresponding red light or green light, thereby achieving full-color display.

[0003] In order to improve the light extraction efficiency of quantum dots, a highly reflective metal bank can be used as the pixel definition layer of quantum dots. When making a metal bank, due to the high production cost of the fine mask (FMM) for patterned evaporation, a simple full-surface evaporation solution can be used. However, full-surface evaporation often forms a metal film at the bottom of the bank, which will inevitably block the transmission of the light emitted by the quantum dots, thereby seriously reducing the display brightness. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the present application provides a color filter substrate that can improve light extraction efficiency.

[0005] The present application provides a color filter substrate, comprising:

[0006] substrate substrate;

[0007] A plurality of retaining wall structures arranged in an array and disposed on the substrate;

[0008] A pixel unit region disposed on the substrate and located between adjacent retaining wall structures;

[0009] Wherein, the surface of the retaining wall structure has a metal film layer, and the metal film layer includes silver.

[0010] Optionally, in some embodiments of the present application, the retaining wall structure includes a first retaining wall disposed on the substrate, and a second retaining wall disposed on a side of the first retaining wall away from the substrate.

[0011] Optionally, in some embodiments of the present application, the metal film layer is disposed on the surface of the second retaining wall.

[0012] Optionally, in some embodiments of the present application, the orthographic projection of the second retaining wall on the first retaining wall completely overlaps with the first retaining wall;

[0013] Furthermore, the orthographic projection of the second retaining wall on the first retaining wall is smaller than the area of ​​the first retaining wall.

[0014] Optionally, in some embodiments of the present application, the thickness of the first retaining wall is 0.5-1 μm.

[0015] Optionally, in some embodiments of the present application, the thickness of the second retaining wall is 5-10 μm.

[0016] Optionally, in some embodiments of the present application, the thickness of the metal film layer is 40 to 60 nm.

[0017] Optionally, in some embodiments of the present application, the surface of the metal film layer has fluorine-containing silane.

[0018] Optionally, in some embodiments of the present application, the pixel unit region includes a red pixel unit region, a green pixel unit region and a blue pixel unit region. The red pixel unit region has red quantum dots, the green pixel unit region has green quantum dots, and the blue pixel unit region is vacant.

[0019] Optionally, in some embodiments of the present application, the width of one end of the second retaining wall in contact with the first retaining wall is smaller than the width of the other end opposite thereto.

[0020] Optionally, in some embodiments of the present application, a protective layer is further provided on the pixel unit area.

[0021] Optionally, in some embodiments of the present application, the material of the protective layer includes SiOx or SiNx.

[0022] Accordingly, the present application also provides a method for preparing a color filter substrate, comprising the following steps:

[0023] The entire surface of the substrate is patterned by using a photolithography process to divide the barrier wall area and the pixel unit area;

[0024] Making a retaining wall structure in the retaining wall region of the substrate;

[0025] A metal film layer is evaporated on the entire surface of the base substrate; the metal film layer comprises silver;

[0026] A metal etching liquid is printed in the pixel unit area to remove the metal film layer in the pixel unit area between adjacent retaining wall structures. The metal etching liquid can be an acidic solution.

[0027] Optionally, in some embodiments of the present application, the fabrication of the retaining wall structure includes: fabricating a first retaining wall on the base substrate, and then fabricating a second retaining wall on the first retaining wall.

[0028] Optionally, in some embodiments of the present application, before printing the metal etching solution, fluorine-containing silane is evenly coated on the metal film layer to improve the wettability of the metal film layer and prevent the metal etching solution from climbing later.

[0029] Optionally, in some embodiments of the present application, the method for preparing the color filter substrate further comprises: performing full-surface evaporation deposition of a protective layer on the base substrate. The protective layer can not only prevent oxidation of the metal film layer, but also play a role in packaging protection.

[0030] Optionally, in some embodiments of the present application, red or green quantum dot material is inkjet printed in the pixel unit area between the retaining walls, and a quantum dot film is formed after UV light curing.

[0031] In addition, the present application also provides a display panel, including the color filter substrate as described above or the color filter substrate prepared by the preparation method described above; and also including a driving backplane, the color filter substrate and the driving backplane are arranged opposite to each other; wherein the driving backplane has a blue backlight.

[0032] The beneficial effects of this application are:

[0033] The present application mainly provides a method for making a patterned metal retaining wall and a process and display panel thereof. After the entire surface is evaporated with metal, the present application adopts a scheme of inkjet printing a metal etching liquid inside the retaining wall to remove the metal at the bottom of the retaining wall, thereby improving the light extraction efficiency. In addition, in order to prevent the etching liquid from climbing up the retaining wall due to capillary action, the present solution constructs a double retaining wall structure that is narrow at the top and wide at the bottom to prevent the etching liquid from climbing, or performs super-hydrophobic technology on the single retaining wall to improve the wettability of the retaining wall surface and prevent the etching liquid from climbing. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 is a schematic structural diagram of a color filter substrate provided in an embodiment of the present application;

[0036] Figure 2 is a schematic diagram of manufacturing a metal film layer on a color filter substrate provided in an embodiment of the present application;

[0037] Figure 3 It is a schematic diagram of the structure of the display panel provided in the embodiment of the present application.

[0038] Explanation of the reference numerals: 10, base substrate; 20, retaining wall structure; 23, second retaining wall; 25, metal film layer; 30, pixel unit area; 31, quantum dot film; 40, driving backplane; 41, blue backlight. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise stated, the directional words such as "upper" and "lower" used generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; while "inside" and "outside" refer to the outline of the device.

[0040] The embodiments of the present application provide a color filter substrate and a method for preparing the same, and a display panel. The following are detailed descriptions of each embodiment. It should be noted that the description order of the following embodiments is not intended to limit the preferred order of the embodiments.

[0041] The present application embodiment provides a color filter substrate 100, see Figure 1 , comprising: a base substrate 10, a retaining wall structure 20, and a pixel unit region 30. Further, the retaining wall structure 20 is disposed on the base substrate 10; and the retaining wall structure 20 has a plurality of retaining wall structures 20 and is arranged in an array on the base substrate 10. The pixel unit region 30 is disposed on the base substrate 10, and the pixel unit region 30 is located between adjacent retaining wall structures 20.

[0042] The surface of the retaining wall structure 20 has a metal film layer 25. Further, the metal film layer 25 includes metal silver. Further, metal silver has a high reflective effect. The metal film layer 25 enables the reflectivity of the retaining wall structure 20 to reach more than 90%, thereby improving the light extraction efficiency of quantum dots, and is expected to be applied to the field of quantum dot high-end display.

[0043] Please continue reading Figure 1 The retaining wall structure 20 includes a first retaining wall 21 disposed on the base substrate 10 , and a second retaining wall 23 disposed on a side of the first retaining wall 21 away from the base substrate 10 .

[0044] Further, the orthographic projection of the second retaining wall 23 on the first retaining wall 21 completely overlaps with the first retaining wall 21, and the orthographic projection of the second retaining wall on the first retaining wall is smaller than the area of ​​the first retaining wall. It can be imagined that the width of the second retaining wall 23 is smaller than the width of the first retaining wall 21. Further, the width of one end of the second retaining wall 23 in contact with the first retaining wall 21 is smaller than the other end opposite thereto. In other words, the second retaining wall 23 is a structure that is narrow at the top and wide at the bottom.

[0045] Furthermore, the overall structure of the retaining wall structure 20 is narrow at the top and wide at the bottom.

[0046] Furthermore, the metal film layer 25 is disposed on the surface of the second retaining wall 23 .

[0047] In some embodiments of the present application, the surface of the metal film layer 25 has fluorine-containing silane. For example, the fluorine-containing silane may be perfluorooctyltrichlorosilane.

[0048] For example, in one embodiment, the color filter substrate 100 includes:

[0049] Base substrate 10;

[0050] A plurality of retaining wall structures 20 arranged in an array and disposed on the base substrate 10;

[0051] A pixel unit region 30 is disposed on the base substrate 10 and between adjacent retaining wall structures 20; wherein the surface of the retaining wall structure 20 has a metal film layer 25, and the metal film layer 25 includes silver. At this time, the retaining wall structure 20 can be a single-layer structure with a narrow top and a wide bottom, such as the structure of the second retaining wall. Furthermore, the surface of the metal film layer 25 has fluorine-containing silane to improve its wettability and prevent the subsequent metal etching solution from climbing.

[0052] For example, in another embodiment, the color filter substrate 100 includes:

[0053] Base substrate 10;

[0054] A plurality of retaining wall structures 20 arranged in an array and disposed on the base substrate 10;

[0055] The pixel unit region 30 is disposed on the base substrate 10 and between adjacent retaining wall structures 20; wherein the retaining wall structure 20 includes a first retaining wall 21 disposed on the base substrate 10, and a second retaining wall 23 disposed on the side of the first retaining wall 21 away from the base substrate 10, and the surface of the second retaining wall 23 has a metal film layer 25, and the metal film layer 25 includes silver. At this time, the retaining wall structure 20 can be a double-layer structure with a narrow top and a wide bottom.

[0056] For example, in another embodiment, the color filter substrate 100 includes:

[0057] Base substrate 10;

[0058] A plurality of retaining wall structures 20 arranged in an array and disposed on the base substrate 10;

[0059] A pixel unit area 30 is arranged on the base substrate 10 and located between adjacent retaining wall structures 20; wherein the retaining wall structure 20 includes a first retaining wall 21 and a second retaining wall 23; the surface of the second retaining wall 23 has a metal film layer 25, and the surface of the metal film layer 25 has fluorine-containing silane.

[0060] Further, the pixel unit region 30 includes a red pixel unit region, a green pixel unit region and a blue pixel unit region. Specifically, the red pixel unit region has red quantum dots, the green pixel unit region has green quantum dots, and the blue pixel unit region is vacant.

[0061] Further, a quantum dot film 31 is provided in the pixel unit region 30. The quantum dot film 31 includes a red quantum dot film and a green quantum dot film. Specifically, the red pixel unit region has red quantum dots, which can form a red quantum dot film. The green pixel unit region has green quantum dots, which can form a green quantum dot film. The blue pixel unit region is vacant.

[0062] In some embodiments of the present application, the thickness of the first retaining wall may be 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm or 1 μm.

[0063] In some embodiments of the present application, the thickness of the second retaining wall is 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm.

[0064] In some embodiments of the present application, the thickness of the metal film layer is 40 nm, 45 nm, 50 nm, 55 nm or 60 nm.

[0065] In some embodiments of the present application, a protective layer (not shown in the figure) is also provided on the color filter substrate 100. It can be imagined that the protective layer is located on the retaining wall structure 20 and the quantum dot film 31 to encapsulate the color filter substrate. The protective layer can prevent the oxidation of the metal film layer (such as Ag) and also plays the role of encapsulating the protective substrate. Furthermore, the material of the protective layer includes silicon oxide (SiOx) or silicon nitride (SiNx).

[0066] Accordingly, the present application also provides a method for preparing a color filter substrate, comprising the following steps:

[0067] The entire surface of the substrate is patterned by using a photolithography process to divide the barrier wall area and the pixel unit area;

[0068] Making a retaining wall structure in the retaining wall region of the substrate;

[0069] Vapor-depositing a metal film layer on the entire surface of the base substrate;

[0070] Print metal etching liquid in the pixel unit area to remove the metal film layer between adjacent retaining wall structures. Figure 2 The material of the metal film layer may be silver. The metal etching solution may be an acidic solution.

[0071] In some embodiments of the present application, the manufacturing of the retaining wall structure includes: manufacturing a first retaining wall on the base substrate, and then manufacturing a second retaining wall on the first retaining wall.

[0072] In some embodiments of the present application, before printing the metal etching solution, fluorine-containing silane is evenly coated on the metal film layer to improve the wettability of the metal film layer and prevent the metal etching solution from climbing later. The fluorine-containing silane can be prepared using perfluorooctyltrichlorosilane solution.

[0073] The method for preparing the color filter substrate further includes: performing full-surface vapor deposition of a protective layer on the base substrate to prevent oxidation of the metal film layer and to provide packaging protection.

[0074] The red or green quantum dot material is inkjet printed in the pixel unit area between the retaining walls, and a quantum dot film is formed after UV light curing.

[0075] After the entire surface is evaporated with metal, the embodiment of the present application adopts a scheme of inkjet printing metal etching liquid between the retaining walls to remove the metal at the bottom of the retaining walls and the metal in the pixel unit area between them, thereby improving the light extraction efficiency. In addition, in order to prevent the etching liquid from climbing up the bank due to capillary action, this scheme constructs a double retaining wall structure with a narrow top and a wide bottom to prevent the etching liquid from climbing, or performs super-hydrophobic technology on a single bank to improve the wettability of the retaining wall surface and prevent the etching liquid from climbing.

[0076] For example, the method for preparing the color filter substrate may include the following steps:

[0077] S1. First, a patterned BM\R\G\B is prepared on a glass substrate using a photolithography process, and then a double barrier wall (transparent or other color) film layer is made, wherein the first barrier wall has a smaller thickness (about 1 μm), and the second barrier wall has a larger thickness (more than 5 μm) and a width slightly smaller than the first barrier wall;

[0078] S2. Vapor-deposit a metal (such as Ag, etc.) of a certain thickness (such as 50 nm) on the double retaining wall to make its reflectivity reach more than 90%;

[0079] S3. Precisely print a small amount of acid solution in the grooves between the first layer of retaining walls by inkjet printing to remove the metal at the bottom of the retaining walls to prevent it from blocking the transmission of quantum dot excitation light;

[0080] S4, inkjet printing red and green quantum dot inks in the grooves between adjacent retaining walls, and curing with ultraviolet (UV) light to form a quantum dot film;

[0081] S5. Vapor-deposit a SiOx or SiNx layer on the entire surface of the post-processed patterned substrate to prevent oxidation of metal Ag and to provide packaging protection.

[0082] For example, the method for preparing the color filter substrate may include the following steps:

[0083] S1. First, a patterned BM\R\G\B\Bank structure is prepared on a glass substrate using a photolithography process, wherein the thickness of the barrier wall (Bank) is more than 5 μm;

[0084] S2, evaporating a certain thickness (e.g. 50nm) of metal (e.g. Ag, etc.) on the retaining wall to make its reflectivity reach more than 90%;

[0085] S3, using spraying or other methods to evenly coat the fluorine-containing solution (perfluorooctyltrichlorosilane, etc.) on the above metal layer to improve its wettability and prevent the subsequent metal etching solution from climbing;

[0086] S4. Precisely print a trace amount of acidic solution in the gaps / grooves between the hydrophobic treated retaining walls by inkjet printing to remove the metal Ag at the bottom of the retaining walls to prevent it from blocking the transmission of the quantum dot excitation light;

[0087] S5, inkjet printing red and green quantum dot inks in the grooves between adjacent retaining walls, and forming quantum dot films after UV light curing;

[0088] S6. Vapor-deposit a SiOx or SiNx layer on the entire surface of the post-processed patterned substrate to prevent oxidation of Ag and to provide packaging protection.

[0089] In addition, the present application also provides a display panel, see Figure 3 , including the color filter substrate 100 as described above; and also including a driving backplane 40, wherein the color filter substrate 100 is arranged opposite to the driving backplane 40; wherein the driving backplane 40 has a blue backlight 41. The blue backlight can be OLED, miniLED or microLED.

[0090] Furthermore, a TFT driving backplane with a blue backlight is assembled and bonded to the color filter substrate (quantum dot substrate); the substrate is subjected to module manufacturing processes such as COF binding and PCB binding, and finally a quantum dot display is obtained.

[0091] In summary, this application mainly provides a method for making a patterned metal retaining wall and a process thereof and a QD-LED display panel, and the color filter substrate of this application can improve the light extraction efficiency, and use a highly reflective metal layer structure to improve the light extraction efficiency of quantum dots, which is expected to be applied to the field of high-end quantum dot displays. The retaining wall structure of this application and the color filter substrate obtained by the preparation method of this application remove the metal at the bottom of the retaining wall and in the pixel unit area, thereby effectively improving the light extraction efficiency.

[0092] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0093] The above is a detailed introduction to a color filter substrate, a preparation method thereof, and a display panel provided in the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for technicians in this field, according to the ideas of the present application, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A color filter substrate, characterized in that: include: substrate substrate; A plurality of retaining wall structures arranged in an array and disposed on the substrate; A pixel unit region disposed on the substrate and located between adjacent retaining wall structures; Wherein, the surface of the retaining wall structure has a metal film layer, and the metal film layer includes silver; The thickness of the metal film layer is 40-60 nm; the surface of the metal film layer has fluorine-containing silane; The fluorine-containing silane is used to improve the wettability of the metal film layer and prevent the metal etching solution from climbing in the later stage.

2. The color filter substrate according to claim 1, characterized in that: The retaining wall structure comprises a first retaining wall arranged on the substrate, and a second retaining wall arranged on a side of the first retaining wall away from the substrate.

3. The color filter substrate according to claim 2, characterized in that: The metal film layer is arranged on the surface of the second retaining wall.

4. The color filter substrate according to claim 2, wherein: The orthographic projection of the second retaining wall on the first retaining wall completely overlaps with the first retaining wall; Furthermore, the orthographic projection of the second retaining wall on the first retaining wall is smaller than the area of ​​the first retaining wall.

5. The color filter substrate according to claim 2, wherein: The thickness of the first retaining wall is 0.5-1 μm; and / or The thickness of the second retaining wall is 5-10 μm.

6. The color filter substrate according to claim 2, wherein: A protective layer is also disposed on the pixel unit area; and / or The width of one end of the second retaining wall in contact with the first retaining wall is smaller than the width of the other end opposite thereto; and / or The pixel unit region includes a red pixel unit region, a green pixel unit region and a blue pixel unit region.

7. A method for preparing a color filter substrate, characterized in that: The steps include: The entire surface of the substrate is patterned by photolithography to divide the barrier wall area and the pixel unit area; Making a retaining wall structure in the retaining wall region of the substrate; Vapor-depositing a metal film layer on the entire surface of the substrate; wherein the metal film layer comprises silver; Printing a metal etching liquid in the pixel unit area to remove the metal film layer in the pixel unit area between adjacent retaining wall structures; Before printing the metal etching solution, the method further includes uniformly coating the fluorine-containing silane on the metal film layer to improve the wettability of the metal film layer and prevent the metal etching solution from climbing later.

8. The method for preparing a color filter substrate according to claim 7, characterized in that: The manufacturing of the retaining wall structure includes: manufacturing a first retaining wall on the substrate, and then manufacturing a second retaining wall on the first retaining wall.

9. The method for preparing a color filter substrate according to claim 7, wherein: The method for preparing the color filter substrate further comprises: performing full-surface vapor deposition of a protective layer on the base substrate; and / or The red or green quantum dot material is inkjet printed in the pixel unit area between the retaining walls and solidified into a film.

10. A display panel, characterized in that: A color filter substrate comprising any one of claims 1 to 6 or a color filter substrate prepared by the preparation method of any one of claims 7 to 9; and a driving backplane, wherein the color filter substrate is arranged opposite to the driving backplane; Wherein, the driving backplane has a blue backlight.

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